U.S. regulators have approved Tuesday another COVID-19 booster, this time for those 50+. It is an additional step in order to protect the most vulnerable against the possibility of coronavirus rebound.
The Food and Drug Administration’s decision opens a fourth dose of the Pfizer or Moderna vaccines to those people at least four months after their previous booster.
The FDA has approved fourth doses for patients 12 years and over who are severely immune compromised. According to the FDA, this group can receive an additional boost with a fifth shot.
The latest expansion, regardless of people’s health, allows an extra shot to millions more Americans — and the question is whether everyone who’s eligible should rush out and get it. It is likely that the Centers for Disease Control and Prevention will weigh in.
It comes amid great uncertainty. Following the Omicron variant winter surge, the number of COVID-19-related cases has dropped to low numbers. CDC data indicate that the two vaccine doses and a booster offer strong protection against serious disease and death.
But an Omicron sibling is causing causing a worrisome jump in infections in Europe — and spreading in the U.S. — even as vaccination has stalled. About two-thirds of Americans are fully vaccinated, and half of those eligible for a first booster haven’t gotten one.
Pfizer had asked the FDA to clear a fourth shot for people 65 and older, while Moderna requested another dose for all adults “to provide flexibility” for the government to decide who really needs one.
There’s limited evidence to tell how much benefit another booster could offer right now. FDA reached the final decision in their absence of input from an independent panel made up of expert witnesses who have weighed how many data points are needed to increase shots.
“There might be a reason to top off the tanks a little bit” for older people and those with other health conditions, said University of Pennsylvania immunologist E. John Wherry, who wasn’t involved in the government’s decision.
But while he encourages older friends and relatives to follow the advice, the 50-year-old Wherry — who is healthy, vaccinated and boosted — doesn’t plan on getting a fourth shot right away. With protection against severe illness still strong, “I’m going to wait until it seems like there’s a need.”
The Omicron mutant is not as resistant to the COVID-19 vaccines as the earlier variants of the virus. Protection against milder infections decreases over time. The immune system has multiple defenses and is able to prevent severe illness or death.
During the U.S. Omicron wave, two doses were nearly 80% effective against needing a ventilator or death — and a booster pushed that protection to 94%, the CDC recently reported. Vaccine effectiveness was lowest — 74% — in immune-compromised people, the vast majority of whom hadn’t gotten a third dose.
U.S. healthcare officials were also interested in Israel during the Omicron spike, when it opened a fourth dose for people over 60 who had not received their first shot within at most four months. The preliminary data that was published online last week indicated some benefits: Israeli scientists logged 92 deaths among the more than 328,000 individuals who had received an extra shot. This compares to the 232 deaths of the 234,000 who didn’t get the fourth dose.
What’s far from clear is how long any extra benefit from another booster would last, and thus when to get it.
“The ‘when’ is a really difficult part. Ideally we would time booster doses right before surges but we don’t always know when that’s going to be,” said Dr. William Moss of the Johns Hopkins Bloomberg School of Public Health.
A longer time interval between shots can help the immune system build a more robust, cross-reactive defense.
“If you get a booster too close together, it’s not doing any harm — you’re just not going to get much benefit from it,” said Wherry.
It’s possible that the latest booster expansion will not be the last. Next week, the government holds a meeting to determine if anyone eventually requires a fourth dose (either in the fall of the original shot or an updated one).
As for updating vaccines, studies in people — of Omicron-targeted shots alone or in combination with the original vaccine — are underway. The National Institutes of Health recently tested monkeys and found “no significant advantage” to using a booster that targets just Omicron.
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